As Michele Bachmann contends for the Republican nomination, we might ask what her Tea Party means for her native midwest. In southwestern Ohio, where I was born and raised, mantras of low taxation and small government have become the way to avoid discussing the challenges of globalisation. Beneath this region's soothing triple green of maize, soybeans, and copses of trees is a soil that serves the world. Places like Clinton County, where my family has lived for two centuries, are the American epicentres of an inspiring but pitiless global economy. Global competition has made family farming here all but impossible, and the region's sowing and reaping is now done by combines that are in effect mobile, high-tech agricultural factories. The labourers no longer needed in the countryside found work in these parts with the international courier service DHL, which in the last decade used Clinton County as its domestic hub. When parent company Deutsche Post suddenly closed DHL's US domestic operations in 2008, 7,000 men and women lost their jobs.

Clinton County is a good example of what happens when harsh global economics go unsoftened by policies of national welfare. The county seat, Wilmington, has a population of only about 12,000. Its businesses had already taken a beating from Wal-Mart, and could hardly absorb the unemployed. Most of the 7,000 newly jobless had health insurance through their workplace, and when they lost their jobs, they lost their coverage. Some fell ill or even died from entirely treatable conditions. For the last two years the headlines of the Wilmington newspaper have been dominated by stories of basement labs for the production of methamphetamine, which reporters simply call "meth." In recent weeks this has given way to news of arrests of heroin dealers. Despite or perhaps because of their struggles, the farmers and workers of Clinton Country are overwhelmingly Republican.

When I first heard of Ohioans taking part in the "Tea Party" in 2009, I assumed that the name referred to late-afternoon political networking over scones. The people from my home state whom I knew to be enthusiastically involved had made their fortunes much earlier, and were quite rich. When I realised that the reference was to American colonial tax revolts against Britain of the 1770s, I was dumbstruck. As anyone who went through Ohio's public schools should know, the American patriots of the day were not protesting against paying taxes. They were demanding to be represented by the government that taxed them, which is something quite different. What American patriots opposed was not taxation itself, but taxation without representation.

Taxation without representation is not exactly a problem for wealthy Americans. They are represented by their local, state, and federal elected officials. They are also represented by campaign contributions, lobbies, and personal political access. Their problem, and the country's, is that they are over-represented, and use their over-representation to ensure that the wealthy pay lower taxes than they should. If we must resort to analogies from the 18th century, then those who benefit from the Tea Party are not to be to compared to the American rebels. They are rather the lords of the British parliament, using superior political power to ensure that those in weaker positions bear the necessary burden of taxes.

Patriots pay their share. To refuse to do so in a moment of need, which is just what the Republican leadership did during the negotiations over the federal debt ceiling in July, is to abandon the nation rather than to serve it. The notion that the federal government ought to be starved of resources is not patriotism: it is rightwing anarchism, which corrodes not only the American state but the American nation.

America is defined by its middle classes, and these are ceasing to exist. Belonging to the middle classes means that, without enormous wealth, you do not need to be concerned about the security of your pension, the quality of your children's education, and the reliability of your family's health care. At this point few people in Clinton County can say (despite some good public schools) that they are worried about none of these. The Dayton and Cincinnati suburbs to the northwest and south-west of Clinton County were once bastions of the middle classes; today anyone in his right mind who lives in these places is also worried about at least two and usually all three of these things.

To have the kind of security that the Canadian or European welfare state provides to its middle classes, my high-school friends in southwestern Ohio would have to earn, by their own estimation, about $300,000 (£182,000) a year. They strive towards this, but naturally (in most cases, if not quite all) fail to attain it. One high-school friend, a Republican from the cradle who has never set foot beyond Ohio, told me that he was thinking of emigrating to Canada. It would be an understatement to say that I never expected to hear this. His problem was not that he believes that he pays too much in taxes. His problem was a debt-ceiling deal that, to his mind, spared those who should be paying a lot more .

The Tea Party's attempt to identify with colonial America is easy to mock; but the danger of mocking midwesterners who like its logic is that they come to seem like exotica. It is hard not to smile, I'll admit, at farmers who plant genetically-engineered seeds six days a week and (like Michele Bachmann) deny evolution on the seventh. One church in Clinton County features a giant pink plastic replica of a horseshoe crab in its garden. Every so often Evel Knievel's former bodyguard jumps it with a motorcycle. The arthropod is a refugee from the Creation Museum in Kentucky, where it took up space that was needed for a parking lot. The crab is supposed to prove that evolution never happened, since its basic form has remained unchanged.

You don't have to look hard to find the massive zoological change that has visited the area. Farmers following ploughs used to find trilobites along with Indian arrowheads, and any visitor to Caesar Creek Nature Preserve can find brachiopods, bryozoa, and horned corals in its exposed layers of limestone, as I did as a child and as my nieces and nephews did last week. Clinton County was also home to the outstanding historian of Victorian intellectual life, Frank Turner, professor and provost at Yale University and director of its libraries. Among other things, Frank studied the influence of evolutionary theory on society. At Frank's memorial service at Yale after his untimely death last year, a fellow midwesterner of his generation recalled the charm and the decline of Wilmington, his hometown. At Frank's request, the reading at the service was from the "Origin of Species".

As Ohio goes, we say, so goes the nation. It seems to me that we can go either way: adapt, or thrill to our own destruction. Clinton County has the plastic horseshoe crab, but also the memory of Frank Turner. Ohio gave the world today's Republican majority leader John Boehner, but also Benjamin Franklin Wade, the Republican senator who helped draft the 14th Amendment to the Constitution. Wade's provision that the American public debt "shall not be questioned" has just been violated by Boehner. The Tea Party, in Ohio as throughout the nation, has found a strategy that is adaptive for itself, if maladaptive for the country: tell those who suffer from Republican policies that anyone who wishes to help them is an outsider. This summer I saw, for the first time that I can remember, a confederate flag flying before an Ohio farmhouse. Radical Republicans like Benjamin Franklin Wade and liberal Republicans like Frank Turner are pretty much extinct. The Democrats, here as elsewhere, are forced back into the position of unwilling conservatives, preserving the republic from the rightwing anarchist view that those who have wealth should not be taxed and that those who do not should thank the Lord for the chaos that ensues.

What is needed is a truly patriotic position, one that would explain to voters, whatever their sympathies, that there is no American nation without an American middle class, and no American middle class without an American government that provides the essential services that allow people to move up in a globalised world. Whatever one thinks of the Tea Party's Orwellian references to our revolutionary heritage, there's no danger of a return to an 18th century: when Ohio did not even exist, and the midwestern economy depended on the Indian flint arrowheads that today pass beneath the blades of the massive high-tech combines. The real danger is that we will move briskly forward to national non-existence, misunderstanding the plainest lessons of our own past along the way. By the time the costs of rightwing anarchism reach the truly privileged, it will be far too late for everyone else. If we don't find a way to adapt own national thinking to global reality before then, all we can look forward to is leaving a trace: like fossils, or arrowheads, or the mammoth tusk that hangs on my grandmother's porch.